微量分光光度法测定饮用水中的亚硝酸盐氮

Determination of nitrite nitrogen in drinking water by micro-spectrophotometry

目的建立测定生活饮用水中亚硝酸盐氮的重氮偶合微量分光光度法。方法利用亚硝酸盐与对氨基苯磺酰胺重氮化,再与盐酸N-(1-萘)-乙二胺产生偶合反应,生成紫红色的偶氮染料的原理,采用自主研制的能够自动进样、自动计算结果、自动清洗的微量自动分析仪及其配套的分析试剂盒,对饮用水中的亚硝酸盐氮进行测定。结果饮用水中亚硝酸盐氮的浓度为0.001 mg/L^0.2 mg/L时,线性关系良好,线性方程为y=3.006 5x+0.004 9,相关系数(r)为0.999 9,检出限为0.001 mg/L,回收率为95.0%~96.8%,相对标准偏差(RSD)为0.0%~0.6%。该方法与国家标准方法进行比较验证,2种方法的测定结果无统计学意义。结论该方法较国家标准方法减少了98%的样品用量及95%的化学试剂用量,产生的废水、废液少,准确度好、操作方便、维护简单,检出限满足国家标准限值的要求,适用于水中亚硝酸盐氮的测定。

Objective To establish a method of micro- spectrophotometry for the determination of nitrite nitrogen in drinking water. Methods Base on the reactions of nitrite with sulfanilic amide and N-（ 1- naphthal）- ethylenediamine to form violet red azo dye,the nitrite nitrogen was quantified by trace automatic analyzer and matched colorimetric assay kit which can automatically sample,calculate and clean. Results A good linear relation was found when the concentrations of nitrite nitrogen and the absorbance in the range of 0. 001 mg / L- 0. 2 mg / L. The linear regulation was y = 3. 006 5x ＋ 0. 004 9,and the correlation coefficient was 0. 999 9. The limit of detection was 0. 001 mg / L,the recovery rates were among 95. 0%- 96. 8% and RSD was0. 0%- 0. 6%. The method was validated with the national standard method and it was found that there was no statistical significance on difference between the two methods. Conclusion The method can reduce 98% of the sample dosage and 95% chemical reagent dosage,compared with the national stardard method,and produce less waste liquid. The method is precisive,simple and easy to maintain. The limit of detection can meet the requirement of national standard limit. It is suitable for the analysis of nitrite nitrogen in water.